Intel HD Graphics 4000 Slow Refresh Rate in Battery Mode

In some Dell laptops with integrated Intel HD Graphics 4000 GPU, a power saving feature called Display Refresh Rate Switching allows the GPU to lower the monitor’s refresh rate to save energy when in Battery mode. However this setting might cause undesirable changes to the brightness/contrast of the monitor and the apparent sluggishness of the system which is very annoying.

To turn off the ‘feature’, open up the Intel HD Graphics Control Panel, then go to the Power section. Select Off in the Display Refresh Rate Switching item and you’re done.